Worst ab exercise - who needs those disks
by Grace Garne
A supine twist with the torso face-up on the floor and the legs in the air will put damaging torsion on lumbar disks. In commision of the exercise, the legs are lowered to the floor on either side causing the spine to rotate.
This move is promoted by many health professionals and trainers who seem to have forgotten that in the general population their is a severe lack of deep abdominal strength. The legs are around sixty percent of a person's total mass. To compress an already vulnerable area's vertebral disks with this much force is downright scary. You don't need a bogus fitness toy to damage your back!
Having ranted, I would add that a leverage-reducting modification turns this from a risk to a return, ex: fix the lower body in place and rotate the torso. Less experienced exercisers stay further away from trouble this way-if their transversus abdominals, internal obliques, pelvic floors, adductors, multifidius, and sacro-spinalis muscles are under conditioned, gravity induced intensity causes them to reduce their range of motion.
Another great modification (for the ball-workout spinal twist on this website) is to hold the ball to the ceiling between the ankles and alternate lifting one side of the sacrum and then the other, keeping the ball centered. One ankle will move up, the other will move down rolling along the ball a bit, the fun part is to keep the ball lined up with the midline of the body and the movement on the tranverse plane (avoid hip-hiking).
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